I want to create some fairly complex 2d predefined paths for my AI sprites to follow.

I'll need to use curves, splines etc to get the effect I want.

Is there a drawing tool out there that will allow me to draw such curves, "mesh" them by placing lots of points along them at some defined density and then output the coordinates of all of those points for me?

I could write this tool myself but hopefully one of the drawing packages can do this?

Alternatively, you could try using my VectorLevelProcessor content pipeline processor, which parses SVG files & path data and can generate point list for bézier curves. But it might be too much work to integrate if you only need a few paths.

I recommend that you don't do this. For a useful blog post, with some video demonstrations, see Fixing Pathfinding Once and For All. Some of the most annoying pathing bugs in Everquest are due to the older zones and their waypoint graphs (also known as lattice pathing), where it looks like the NPCs ride on rails once they've reached the mesh.